Forensic Toxicology Practice Questions

Q: A 34-year-old female with a diagnosis of borderline personality disorder presented to the casualty with a history of poison consumption following an argument. She was reluctant to disclose the consumed substance. She was initially treated with stomach wash and IV fluids. After one week, she developed jaundice, ascites, and encephalopathy. What is the likely poison responsible for acute liver failure?

Zinc phosphide. ### Explanation **Correct Option: A. Zinc phosphide** Zinc phosphide is a common rodenticide that causes multi-organ failure. The clinical presentation typically follows a **biphasic pattern**. Initially, patients present with gastrointestinal irritation (nausea, vomiting, abdominal pain). This is followed by a "latent period" or a delayed phase (usually 48 hours to several days later) characterized by **severe hepatotoxicity**, leading to jaundice, ascites, and hepatic encephalopathy (Acute Liver Failure). In the context of Borderline Personality Disorder (BPD), impulsive self-harm via rodenticide ingestion is a frequent clinical scenario. **Analysis of Incorrect Options:** * **B. Pyrethrum:** These are insecticides with low mammalian toxicity. Poisoning usually presents with hypersensitivity reactions, dermatitis, or respiratory symptoms (asthma), but not acute liver failure. * **C. Ethylene Glycol:** Found in antifreeze, this primarily causes a high anion gap metabolic acidosis and **Acute Kidney Injury (AKI)** due to calcium oxalate crystal deposition in renal tubules. It does not typically cause primary acute liver failure. * **D. Carbamate poisoning:** Similar to organophosphates, these inhibit acetylcholinesterase. Presentation involves a **cholinergic crisis** (SLUDGE: Salivation, Lacrimation, Urination, Defecation, GI distress, Emesis). Death usually occurs due to respiratory failure, not delayed hepatic failure. **High-Yield Clinical Pearls for NEET-PG:** * **BPD & Self-Harm:** Patients with BPD often use "parasuicidal" gestures (non-fatal self-harm) as a cry for help or to regulate intense affect. * **Zinc Phosphide "Garlic Odor":** A classic sign is a distinct garlic-like odor in the breath or vomitus due to the release of phosphine gas. * **Hepatotoxicity Triad:** When a question mentions delayed jaundice and encephalopathy after poisoning, think of **Zinc Phosphide, Paracetamol (Acetaminophen), or Carbon Tetrachloride.**

Q: Delirium can occur from poisoning of which of the following?

Digitalis. **Explanation:** **Digitalis (Option D)** is the correct answer because it is a classic example of a **Cerebral Poison**. While primarily known for its cardiotoxic effects (arrhythmias), digitalis toxicity frequently manifests with significant Central Nervous System (CNS) disturbances. These include headache, fatigue, malaise, and mental confusion progressing to **delirium**, hallucinations, and even convulsions. The mechanism involves the inhibition of the Na+/K+-ATPase pump, which alters neuronal excitability. **Analysis of Incorrect Options:** * **Lead (Option A):** Lead poisoning (Plumbism) typically presents with encephalopathy (especially in children), peripheral motor neuropathy (wrist drop/foot drop), and gastrointestinal symptoms (colic). While it affects the brain, "delirium" is not its hallmark acute presentation compared to digitalis. * **Copper (Option B):** Copper poisoning primarily acts as an **Irritant Poison**. It causes severe gastrointestinal distress (blue-green vomitus), metallic taste, and can lead to hemolysis and hepatic/renal failure (Wilson’s disease-like presentation), but not primary delirium. * **Arsenic (Option C):** Arsenic is a potent **protoplasmic poison**. Acute poisoning presents with "rice-water stools" (mimicking cholera) and shock. Chronic poisoning leads to skin changes (raindrop pigmentation) and hyperkeratosis, rather than acute delirium. **NEET-PG High-Yield Pearls:** * **Deliriant Poisons:** The classic triad of deliriant poisons includes **Dhatura, Belladonna, and Hyoscyamus** (all anticholinergics). Digitalis is a high-yield "non-anticholinergic" cause of delirium. * **Visual Disturbance:** A unique feature of Digitalis toxicity is **Xanthopsia** (yellow-tinted vision). * **ECG in Digitalis:** Look for the "Reverse Tick" sign or "Sagging ST segment." * **Antidote:** Digoxin-specific antibody fragments (DigiFab).

Q: Which of the following is NOT a sign or symptom of aconite poisoning?

Hypertension. **Explanation:** Aconite poisoning (derived from *Aconitum napellus*, also known as "Monkshood" or "Sweet Poison") acts primarily as a **sodium channel activator**, keeping channels open and leading to prolonged depolarization of excitable tissues like nerves and muscles. **1. Why Hypertension is the Correct Answer:** Aconite is a potent **cardiotoxin and neurotoxin**. Its primary cardiovascular effect is **Hypotension**, not hypertension. It causes profound bradycardia and peripheral vasodilation, leading to a shock-like state. Therefore, Hypertension is the "odd one out" and the correct answer. **2. Analysis of Other Options:** * **Pain Abdomen:** Aconite is a powerful gastrointestinal irritant. Ingestion typically leads to nausea, vomiting, and severe abdominal pain/colic. * **Bradycardia:** Aconite has a "digitalis-like" action on the heart. It stimulates the vagus nerve, leading to significant bradycardia and various arrhythmias (classically, bidirectional ventricular tachycardia). * **Diplopia:** As a neurotoxin, aconite affects cranial nerves and the central nervous system. This results in visual disturbances like diplopia (double vision), blurred vision, and the characteristic "hippus" (rhythmic pupillary constriction and dilation). **Clinical Pearls for NEET-PG:** * **The "Tingling" Sign:** The most characteristic early symptom of aconite poisoning is a **tingling and numbness** (paresthesia) of the tongue, lips, and skin. * **Respiration:** Death usually occurs due to respiratory failure or cardiac arrhythmias. * **Post-mortem:** No specific findings; however, the "root" may be found in the stomach. * **Treatment:** Primarily supportive; Atropine is used for bradycardia, and Amiodarone/Lidocaine for arrhythmias. * **Synonym:** Often called the **"Queen of Poisons."**

Q: In which poisoning is the vomitus characteristically bluish green?

Bluish green. **Explanation:** The characteristic **bluish-green** color of vomitus is a classic diagnostic sign of **Copper Sulfate (Blue Vitriol) poisoning**. This occurs due to the formation of copper salts (cupric carbonate) when the poison reacts with gastric juices. **Analysis of Options:** * **A. Bluish Green (Correct):** Specifically associated with **Copper Sulfate**. It is important to differentiate this from the greenish vomitus seen in Phosphorus poisoning (which is luminous/phosphorescent) or certain organic irritants. * **B. Black:** Typically seen in **Sulfuric Acid ($H_2SO_4$)** poisoning due to the carbonization of tissues (charring) and the formation of acid hematin. It can also be seen in **Phenol (Carbolic acid)** poisoning. * **C. Brown:** Characteristic of **Nitric Acid ($HNO_3$)** poisoning. This is due to the xanthoproteic reaction, where the acid reacts with proteins to produce yellow/brown picric acid derivatives. * **D. Red Velvety:** This refers to the appearance of the **gastric mucosa** (rather than the vomitus itself) in **Arsenic poisoning**. Arsenic acts as a potent gastrointestinal irritant, causing sub-mucosal hemorrhages that give the stomach lining a "red velvety" appearance. **High-Yield Clinical Pearls for NEET-PG:** * **Copper Sulfate:** Look for systemic features like hemolysis, jaundice, and "Heme-induced" acute tubular necrosis. * **Oxalic Acid:** Vomitus is often described as **"Coffee-ground"** (due to acid hematin). * **Phosphorus:** Vomitus has a **garlicky odor** and is **luminous** in the dark. * **Mercury:** Vomitus may contain grayish-white shreds of mucous membrane.

Q: Plumbism is caused by:

Lead poisoning. **Explanation:** **Plumbism** is the clinical term for chronic **Lead poisoning**. The name is derived from the Latin word *Plumbum* (Pb). Lead is a cumulative heavy metal poison that primarily affects the gastrointestinal, hematological, and nervous systems. **Why Lead Poisoning is Correct:** Chronic exposure to lead leads to the inhibition of the enzyme **ALAD (Aminolevulinic Acid Dehydratase)** and **Ferrochelatase**, disrupting heme synthesis. This results in characteristic clinical features such as **Burtonian lines** (blue-purple lines on gums), **Colic and Constipation**, and **Wrist drop/Foot drop** due to peripheral neuropathy (radial/peroneal nerve palsy). **Why Other Options are Incorrect:** * **Mercury Poisoning:** Known as **Hydrargyrism**. Chronic exposure leads to "Erethism" (peculiar shy behavior), "Pink disease" (Acrodynia), and "Hatters' Shakes" (intention tremors). * **Thallium Poisoning:** Often called the "poisoner's poison." It is characterized by **Alopecia** (hair loss), Mees' lines on nails, and painful peripheral neuropathy. * **Copper Poisoning:** Known as **Chalcosis**. Acute ingestion causes "blue vomitus," while chronic accumulation (as seen in Wilson’s Disease) leads to **Kayser-Fleischer (KF) rings** in the cornea. **High-Yield Clinical Pearls for NEET-PG:** * **Basophilic Stippling:** Punctate basophilia in RBCs is a classic hematological finding in lead poisoning. * **Radiology:** "Lead lines" (increased radiodensity) are seen at the metaphyses of growing long bones in children. * **Treatment:** The drug of choice for lead encephalopathy is **BAL (British Anti-Lewisite)** followed by **EDTA**. For oral treatment in stable patients, **Succimer (DMSA)** is preferred.

Q: Which of the following is the 'ordeal poison' used by tribes of Africa?

Physostigmine. **Explanation:** **Physostigmine (Option A)** is the correct answer. It is a naturally occurring tertiary amine carbamate obtained from the **Calabar bean** (*Physostigma venenosum*). Historically, these beans were used by West African tribes in "trials by ordeal" to determine guilt or innocence. A person accused of a crime would ingest the beans; if they vomited (survived), they were declared innocent, but if they succumbed to the toxic effects (miosis, skeletal muscle paralysis, and respiratory failure), they were deemed guilty. **Why the other options are incorrect:** * **Digoxin (Option B):** A cardiac glycoside derived from *Digitalis lanata*. It is used for heart failure and atrial fibrillation but has no historical association with ordeal trials. * **Cocaine (Option C):** An alkaloid from *Erythroxylum coca* used as a local anesthetic and drug of abuse; it acts as a sympathomimetic. * **Atropine (Option D):** An anticholinergic derived from *Atropa belladonna*. Interestingly, it is the **pharmacological antidote** for physostigmine poisoning, as it competes at muscarinic receptors. **High-Yield NEET-PG Pearls:** * **Lipid Solubility:** Unlike Neostigmine, Physostigmine is a **tertiary amine**, meaning it is lipid-soluble and **crosses the blood-brain barrier (BBB)**. * **Clinical Use:** It is the drug of choice for **Atropine poisoning** (Anticholinergic syndrome). * **Mechanism:** It is a reversible anticholinesterase that increases acetylcholine levels at both muscarinic and nicotinic sites. * **Mnemonic:** "Physostigmine **P**hixes (fixes) the **P**eriphery and the **P**syche (CNS)."

Q: A patient has been allegedly bitten by a cobra snake. The venom in such a bite would primarily be:

Neurotoxic. **Explanation:** The correct answer is **D. Neurotoxic**. **Understanding the Concept:** Snake venoms are complex mixtures of enzymes and proteins categorized based on their primary target organ system. The **Cobra (Naja naja)** and the **King Cobra** belong to the *Elapidae* family. Their venom is predominantly **neurotoxic**. It contains post-synaptic neurotoxins that bind to acetylcholine receptors at the neuromuscular junction. This leads to a blockade of nerve impulse transmission, resulting in progressive muscular paralysis, ptosis (drooping of eyelids), and eventually death due to respiratory failure. **Analysis of Incorrect Options:** * **A. Musculotoxic:** This is characteristic of **Sea Snake** venom. It contains myotoxins that cause rhabdomyolysis, leading to myoglobinuria and potential renal failure. * **B. Vasculotoxic:** This is the hallmark of the **Viperidae** family (e.g., Russell’s Viper, Saw-scaled Viper). Their venom causes endothelial damage, hemolysis, and coagulation defects, leading to internal bleeding and local tissue necrosis. * **C. Cardiotoxic:** While some cobra venoms contain cardiotoxic components that can affect heart rhythm, the *primary* and most immediate life-threatening effect is neurotoxicity leading to respiratory paralysis. **High-Yield Clinical Pearls for NEET-PG:** * **Elapidae (Cobra, Krait):** Primarily Neurotoxic. Krait venom is pre-synaptic, while Cobra is post-synaptic. * **Viperidae (Vipers):** Primarily Vasculotoxic/Hematotoxic. * **Hydrophidae (Sea Snakes):** Primarily Myotoxic. * **The "20-minute Whole Blood Clotting Test" (20WBCT):** The most reliable bedside test to diagnose vasculotoxic (Viper) bites. * **Neostigmine Test:** Often used in Cobra bites to differentiate and potentially reverse neuromuscular blockade.

Q: Which of the following is NOT a feature of chronic cocaine abuse?

Run amok. **Explanation:** The correct answer is **D. Run amok**, as this phenomenon is classically associated with **Cannabis** (Ganja) and occasionally severe alcohol withdrawal, but not cocaine. "Run amok" refers to a state of sudden, spontaneous frenzy where an individual develops a homicidal urge, attacking anyone in their path before falling into a deep sleep or committing suicide. **Analysis of Options:** * **Formication (Magnan’s Symptom):** This is a hallmark of chronic cocaine abuse. It is a tactile hallucination where the user feels as if insects (cocaine bugs) are crawling under the skin. * **Black staining of the tongue:** Chronic cocaine users who smoke the drug (crack) or use it orally often develop a characteristic blackish-brown discoloration of the tongue and teeth due to the deposition of combustion products and localized vasoconstriction. * **Peripheral gangrene:** Cocaine is a potent vasoconstrictor. Chronic use can lead to severe ischemic necrosis and peripheral gangrene, particularly in the extremities or the nasal septum (leading to perforation). **High-Yield Clinical Pearls for NEET-PG:** * **Cocaine (Snow/Coke):** Acts by inhibiting the reuptake of Dopamine, Norepinephrine, and Serotonin. * **Mydriasis:** Cocaine causes marked pupillary dilation (unlike Opioids, which cause miosis). * **Body Packers/Stuffers:** Individuals who swallow packets of cocaine for smuggling; rupture can lead to fatal toxicity. * **Antidote:** There is no specific antidote; management is symptomatic (Benzodiazepines for agitation/seizures). **Beta-blockers are contraindicated** due to the risk of unopposed alpha-adrenergic stimulation.

Q: The term 'cold turkey' is used to denote which of the following?

Abrupt cessation of heroin. **Explanation:** The term **'Cold Turkey'** refers to the **abrupt and complete cessation** of a drug (most commonly heroin or other opioids) to which a person is addicted, rather than a gradual reduction in dosage. **Why Option B is Correct:** The name is derived from the physical appearance of the skin during acute opioid withdrawal. Due to **piloerection** (contraction of the arrector pili muscles), the patient develops "gooseflesh" or "goosebumps." This makes the skin look and feel like the skin of a plucked, refrigerated turkey. This phenomenon is a hallmark sign of the sympathetic nervous system's overactivity during the withdrawal phase. **Why Other Options are Incorrect:** * **Option A:** Consumption of heroin is simply called "using" or "chasing the dragon" (if inhaled). * **Option C:** Gradual withdrawal is a medically supervised process often involving tapering doses or substitution therapy (e.g., Methadone or Buprenorphine) to minimize withdrawal symptoms. * **Option D:** There is no specific forensic or medical term "cold turkey" for a withdrawal facility; these are typically called detoxification centers or rehabs. **High-Yield Clinical Pearls for NEET-PG:** * **Kicking the Habit:** This phrase also originates from heroin withdrawal, referring to the involuntary leg tremors and muscle twitches (restless leg syndrome) experienced by addicts. * **Symptoms of Opioid Withdrawal:** Mydriasis (dilated pupils), lacrimation, rhinorrhea, yawning, sweating, piloerection, and diarrhea. * **Antidote for Acute Opioid Poisoning:** Naloxone (pure opioid antagonist). * **Treatment for Opioid Withdrawal:** Clonidine (to suppress sympathetic overactivity) or Methadone/Buprenorphine (substitution).

Question 1

A 34-year-old female with a diagnosis of borderline personality disorder presented to the casualty with a history of poison consumption following an argument. She was reluctant to disclose the consumed substance. She was initially treated with stomach wash and IV fluids. After one week, she developed jaundice, ascites, and encephalopathy. What is the likely poison responsible for acute liver failure?

Accepted Answer

Zinc phosphide

Answer

Pyrethrum

Answer

Ethylene glycol

Answer

Carbamate poisoning

Question 2

Delirium can occur from poisoning of which of the following?

Accepted Answer

Digitalis

Answer

Lead

Answer

Copper

Answer

Arsenic

Question 3

Which of the following is NOT a sign or symptom of aconite poisoning?

Accepted Answer

Hypertension

Answer

Pain abdomen

Answer

Bradycardia

Answer

Diplopia

Question 4

In which poisoning is the vomitus characteristically bluish green?

Accepted Answer

Bluish green

Answer

Black

Answer

Brown

Answer

Red velvety

Question 5

Plumbism is caused by:

Accepted Answer

Lead poisoning

Answer

Mercury poisoning

Answer

Thallium poisoning

Answer

Copper poisoning

Question 6

Which is not a mechanism of action of corrosive poisons?

Accepted Answer

Free radical oxidative injury

Answer

Extracting water from tissues

Answer

Coagulation of proteins

Answer

Conversion of haemoglobin to hematin

Question 7

Which of the following is the 'ordeal poison' used by tribes of Africa?

Accepted Answer

Physostigmine

Answer

Digoxin

Answer

Cocaine

Answer

Atropine

Question 8

A patient has been allegedly bitten by a cobra snake. The venom in such a bite would primarily be:

Accepted Answer

Neurotoxic

Answer

Musculotoxic

Answer

Vasculotoxic

Answer

Cardiotoxic

Question 9

Which of the following is NOT a feature of chronic cocaine abuse?

Accepted Answer

Run amok

Answer

Peripheral gangrene

Answer

Black staining of the tongue

Answer

Formication

Question 10

The term 'cold turkey' is used to denote which of the following?

Accepted Answer

Abrupt cessation of heroin

Answer

Consumption of heroin

Answer

Gradual withdrawal of heroin

Answer

A place for group drug withdrawal

Forensic Toxicology — MCQs

Forensic Toxicology — MCQs

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